Aluminum alloy



Patented Sept. 2, 1941 UNITED STATES PATENT OFFICE ALUMINUM ALLOY GeorgeEdward Barnes, Cleveland, Ohio No Drawing. Application July 29, 1940,

Serial No. 348,20!

2 Claims.

' to obtain strength.

Another object is to produce an aluminum alloy that may be subjected tocasting, forging, rolling and machining operations without sacrificinghardness and strength and capable of resisting corrosion to a greaterdegree than any other known aluminum alloy.

A further object is to produce an aluminum alloy that when cast may bemachined without the use of any solution, 1. e., in its dry state, thusbeing workable like bronze, any such operation producing a mirror-likefinish free from pits, abrasions and other objectionable effectsheretofore peculiar to machine operations as applied to aluminum alloyparts.

According to this invention, I make a casting alloy by compoundingelements such as may be secured in the purchase of several commercialaluminum alloys of recognized standard quality, then combining thesealloys with commercial aluminum (99% pure) so that the relativequantities under practical foundry practice fall by weight within theranges set out below:

Per cent 30 Copper 4.5 to 6.0 Nickel .5 to 2.0 Magnesium .1 to .25Titanium .1 to .25 Chromium .25 to .5 J5 Balance-Commercial aluminum(99% pure) and traces of other elements.

Total 100.0 40

Mycasting alloy is made in a manner different than commonly used and isbriefly described, as follows: First, I mix the aluminum alloys with thealuminum (99% pure) in the proportions by weight indicated above (or asset forth in the practical examples hereinbelow). Second, I melt thismixture. Third, I then allow the molten mass to soak from fifteen tothirty minutes Fourth, I then pour this molten mass into molds and formingots of my alloy. Fifth, I allow these ingots to rest or age for atleast twenty-four (24) hours before remelting for such purpose as may berequired.

My invention may be more readily perceived r by the practical foundrymanby considering'one typical batch that I have made up for experimentalpurposes, as follows:

Pounds 50/50 copper-aluminum 6 20/80 nickel-aluminum 2 6/94magnesium-aluminum 1 6/94 titanium-aluminum 1% 20/80 chromium-aluminum 1Commercial aluminum (99% pure) 50 This mixture works out approximatelyand by calculation, as follows:

Per cent Aluminum 93.552 Copper 5,200 Nickel .640 Magnesium .144Titanium .144 Chromium .320

Total "100.000

vare termed surface and inside shrink, and

is free from porosity and makes a tight, closegrained casting. Also, myalloy when cast produces parts that may be machined in their dry stateto a mirror-like finish, free from dragging, pits or abrasions, and thusproduces results far superior to those obtained through the use of anyother casting alloys discovered to-date.

My alloy, as illustrated by the above practical example, shows a tensilestrength above 27,000

pounds per square inch when made up in a sand cast test-bar andafterageing for three days. A similar test-bar, after ageing of two to threeweeks, showed a tensile strength of about 30,000 pounds per square inchwith an elongation of slightly more than 2.0%.

. I find the composition of the several standard commercial alloys doesvary from time to time but my tests show uniform results if the elementsso commercially obtained and mixed do not vary if present within theranges set out hereinbefore.

I therefore produce an homogeneous and stable aluminum casting alloywhich may be subjected to forging. rolling and machining, withadvantages and properties for superior to any heretofore discovered.

What I claim is: r

1. A casting alloy composed of the elements 5 in the relative quantitiesby weight within the ranges set out below: 7

' Per cent Copper 4.5 to 6.0 Nickel .5 to 2.0 Magnesium .1 to .25Titanium .1 to .25 Chromium .25 to .5 Aluminum ..The remainder Traces ofimpurities and other elements.

2. A casting alloy composed of the elements in the relative quantitiesby weight as specifically set out below:

(without consideration of traces of other elements and impurities).

GEORGE EDWARD BARNES.

